With the popularity of portable electronic devices and wireless devices that support audio applications, there is a growing need to provide a simple and complete solution for audio communications applications. For example, some users may utilize Bluetooth-enabled devices, such as headphones and/or speakers, to allow them to communicate audio data with their wireless handset while freeing to perform other activities. Other users may have portable electronic devices that may enable them to play stored audio content and/or receive audio content via broadcast communication, for example.
However, integrating multiple audio communication technologies into a single device may be costly. Combining a plurality of different communication services into a portable electronic device or a wireless device may require separate processing hardware and/or separate processing software. Moreover, coordinating the reception and/or transmission of data to and/or from the portable electronic device or a wireless device may require significant processing overhead that may impose certain operation restrictions and/or design challenges. For example, a handheld device such as a cellphone that incorporates Bluetooth and Wireless LAN may pose certain coexistence problems caused by the close proximity of the Bluetooth and WLAN transceivers.
Furthermore, simultaneous use of a plurality of radios in a handheld may result in significant increases in power consumption. Power being a precious commodity in most wireless mobile devices, combining devices such as a cellular radio, a Bluetooth radio and a WLAN radio requires careful design and implementation in order to minimize battery usage. Additional overhead such as sophisticated power monitoring and power management techniques are required in order to maximize battery life.
The Bluetooth subband codec (SBC) is a low computational complexity audio coding system designed to provide high quality audio at moderate bit rates to Bluetooth enabled devices. The Bluetooth SBC system utilizes a cosine modulated filterbank, for example, for analysis and synthesis. The filterbank may be configured for 4 subbands or 8 subbands, for example. The subband signals may be quantized using a dynamic bit allocation scheme and block adaptive pulse code modulation (PCM) quantization. The number of bits available and the number of bits used for quantization may vary, thereby making the overall bit-rate of the SBC system adjustable. This is advantageous for use in wireless applications where the available wireless bandwidth for audio, and the maximum possible bit-rate may vary over time.
The Bluetooth community has developed specifications that define how to use streaming audio over a Bluetooth link. This opens up Bluetooth technology to a whole new class of audio devices, such as wireless stereo headsets, wireless speakers, and wireless portable MP3 players just to name a few. With the introduction of new Bluetooth specifications for streaming audio, new Bluetooth products such as wireless stereo headsets and wireless file streaming applications are becoming a reality. Wireless applications require solutions that are increasingly low power in order to extend battery life and provide a better end user experience. With existing systems, the computational requirements of high fidelity audio coding may make it cost prohibitive and challenging to add features such as streaming music to wireless devices.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.